Locomotive warning horn

ABSTRACT

A sound device particularly adapted for use as a locomotive warning horn characterized by a housing having a vibrator means for converting a constant flow of a gaseous medium into a pulsating flow which is removed from the housing through an outlet passageway having a first portion and a second portion in communication with a horn which extends at an angle to the first portion so that foreign matter entering the horn or resonator is not accumulated on the vibrator means. In one of the preferred embodiments, the outlet passageway of the device has a first portion which merges with a second and third portion both of which extend at an angle to the first portion and each of the second and third portions has a horn associated therewith so that the single vibrator means drives or produces the pulsating flow for both horns or resonators. In this embodiment, various means are utilized to insure a balanced flow of the pulsating gaseous medium through each of the horns, these means can be partitions for splitting the flow, means for restricting or impeding the flow into one portion such as a choke or a passageway with a curved path, a deflecting block at the junction of the portions or an inspirator which changes the boundary layer characteristics of one of the resonators to vary the impedance to the flow through the horn. One or more of these particular means can be utilized in the sound device to insure a balance in the flow therethrough to provide substantially equal strengths in the sounds emitted from each of the two resonators.

United States Patent [191 Heehler et al.

Jan. 16, 1973 [54] LOCOMOTIVE WARNING HORN [75] Inventors: Arthur C. Heehler, Park Ridge; George J. Taylor, Northbrook, both of 111.

[73] Assignee: Mercor Corporation, Franklin Park,

[22]- Filed: Jan. 11, 1971 [21] Appl. No.: 105,585

[52] US. Cl. 116/142 FP, 340/388 [51] Int. Cl. ..G10k 9/00 [58] Field of Search ....1 16/137, 137 A, 142, 142 F1, 116/142 FV; 340/388 [56] References Cited UNITED STATES PATENTS 953,044 3/1910 Macloskie.... .....l16/142 FP 1,692,766 11/1928 Anderson..... ....116/142 FP 1,767,740 6/1930 Buell ....1 16/142 FP 2,263,342 11/1941 Lewis.... ....116/142 FP 2,521,148 9/1950 ,Buell ....1l6/l42 FP 2,579,784 12/1951 Broden ..116/142 R Primary ExaminerLouis J. Capozi Att0rneyl-lill, Sherman, Meroni, Gross & Simpson [5 7 ABSTRACT A sound device particularly adapted for use as a locomotive warning horn characterized by a housing having a vibrator means for converting a constant flow of a gaseous medium into a pulsating flow which is removed from the housing through an outlet passageway having a first portion and a second portion in communication with a horn which extends at an angle to the first portion so that foreign matter entering the horn or resonator is not accumulated on the vibrator means. In one of the preferred embodiments, the outlet passageway of the device has a first portion which merges with a second and third portion both of which extend at an angle to the first portion and each of the second and third portions has a horn associated therewith so that the single vibrator means drives or produces the pulsating flow for both horns or resonators. In this embodiment, various means are utilized to insure a balanced flow of the pulsating gaseous medium through each of the horns, these means can be partitions for splitting the flow, means for restricting or impeding the flow into one portion such as a choke or a passageway with a curved path, a deflecting block at the junction of the portions or an inspirator which changes the boundary layer characteristics of one of the resonators to vary the impedance to the flow through the horn. One or more of these particular means can be utilized inthe sound device to insure a balance in the flow therethrough to provide substantially equal strengths in the sounds emitted from each of the two resonators.

14 Claims, 9 Drawing Figures LOCOMOTIVE WARNING HORN BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is directed to a sound device and particularly to a sound device using a diaphragm for converting a constant flow of gaseous medium into a pulsating gaseous medium.

2. Prior Art Sound devices which utilize a vibrating diaphragm to convert a constant flow of a gaseous medium into a pulsating flow which then is conducted through a horn to produce the desired sound are well known in the prior art. An example of such a device is disclosed in US. Pat. No. 2,579,784 issued on Dec. 25, 1951.

Sound devices of this type have been used as locomotive warning devices and have experienced certain difficulties since the horn of the device usually has a hell or funnel shape and is usually aimed in the forward direction and acts as a scoop for collecting dust, bugs and other foreign particles. Due to the speed of travel of the locomotive this foreign matter is forced into the device and impacted on the diaphragm where it accumulates and interferes with the proper vibrating characteristics during sounding of the device.

SUMMARY OF THEINVENTION The present invention provides an outlet passageway for conveying a pulsating flow of gaseous medium to a horn, which passageway has a first portion extending from a vibrator that has a junction with a second portion extending at an angle to the first portion so that foreign matter entering the horn does not accumulate adjacent to the vibrator to interfere with its operation. In one of the embodiments of the invention, means are provided for introducing a second source of gas under pressure adjacent to the junction of the first and second portion to change the boundary layer characteristic of the horn and thus change the tone of the sound emitted therefrom. I

In a second embodiment of the invention, the outlet passage of the device has two portions extending at an angle to the first portion which is adjacent to the vibrator with each of the two portions having a separate horn associatedtherewith so that the single vibrator provides a pulsating flow of gaseous medium for operating both horns. If horns or resonators of different sound characteristics and impedance characteristic for the pulsating flow are used, means are also provided to insure a balance or equal flow of the pulsating fluid through both of the resonators so that the sound generated therein is of substantially equal strength.

AS SHOWN ON THE DRAWINGS FIG. 1 is a sidev elevation of the sound device of the present invention;

FIG. 2 is a plan elevation taken along lines IIII of FIG. 1:

FIG. 3 is a partial cross-section of the sound device of FIG. 1;

FIG. 4 is a cross-section of the sound device taken along lines IV-IV of FIG. 1;

FIG. 5 is a cross-section similar to FIG. 3 illustrating two forms of changing the impedance of the travel of the pulsating flow through the device;

DESCRIPTION OF THE PREFERRED EMBODIMENTS The principles of the present invention can be employed in many different types of sound devices and is particularly adapted to a locomotive warning horn generally indicated at in FIG. 1. The sound device or horn 10 has a housing 11 comprised of a body portion 12 and a cap portion 13 which are held together by appropriate fastening means such as bolts 14 which are threadably received in threaded bores 15 of the body portion 12 (FIG. 3). Extending from the body portion 12 is a horn or resonator 16 and a second horn or resonator 17 both of which have a bell or funnel-like configuration and may be formed integrally with the body portion as illustrated in FIG. 6 or separately as illustrated in FIG. 3. To mount the sound device or horn 10 on a vehicle such as a locomotive, suitable mounting means such as bores 18 for receiving mounting bolts are provided in the body portion 12.

The housing 11 and particularly the body portion 12 has an inlet passageway 20, an outlet passageway 21 and an annular chamber 22 concentric with the outlet passageway 21 and which chamber 22 has a varying depth as illustrated in FIGS. 3 and 4. The inlet passageway 20, as best illustrated in FIG. 4, is in communication with the annular chamber 22 and is provided with means for connection to a source of pressurized gaseous medium such as compressed air. As illustrated the means comprises a machine. surface 23 for receiving a flange connector and means for holding the connector thereto such as bolt holes 24 (FIG. 1) for receiving mounting bolts.

The outlet passageway 21 has a frusto conical surface 25 at one end which forms an annular lip 26 with the annular chamber 22. The lip 26 extends above the plane of a machine surface 27 of the body portion 12. From the frusto conical surface 25, the outlet passageway 21 has a first portion 28 extending away from the lip and a second portion 29 merging with the first portion at a point of intersection and extending at an angle thereto. As illustrated in FIG. 3, a third portion 30 also merges with the first portion 28 and extends from the point of intersection or merger in the opposite direction and the outlet passageway 21 has a substantially T-shaped cross section with the second and third portions 29 and 30, respectively, being axially aligned and forming an end or base 28a for the first portion 28.

Each of the second and third portions 29 and 30 have an enlarged portion 29a and 30a respectively for receiving a base 16a and 17a of their respective resonators. The bases 16a and 17a can be secured in the enlarged portions 29a and 30a by appropriate means such as the set screws 31 (FIG. 1).

To create a pulsating flow of the pressurized gaseous medium from a constant flow entering the inlet passageway 20, a vibrator means generally indicated at 32 (FIG. 3) is provided. The vibrator means 32 comprises an annular flat ring 33 and a diaphragm 34. The cap 13 has a dome portion 35 surrounded by an annular recess 36 which receives the diaphragm 34 which cooperates with the dome 35 to form a pressure chamber 37. Adjacent the recess 36, the cap 13 has a larger annular recess 38 for receiving the annular ring 33 which is clamped between the cap 13 and the body portion 12.

When the vibrator 32 is assembled, the annular ring 33 is held by the recess 38 tightly against the surface 27 and the inner edge lies on the lip 26. In the clamped condition, the ring 33 is stressed out of its planar orientation so that the ring 33 and the diaphragm 34 have a triangular space 39 therebetween. As best illustrated in FIGS. 8 and 9, the recess 36 is provided with notches 40 which are circumferentially spaced therearound to form ports extending around the diaphragm 34 to allow communication of a medium between the space 39 and the chamber 37.

To allow the gaseous medium in the chamber 37 to return to substantially atmospheric pressure during periods of no operation of the device 10, means are provided to bleed the contents of the chamber 37 therefrom. As illustrated, the means comprise a small orifice 41 in the diaphragm 34.

In operating the sound device 10, a gaseous medium under pressure such as compressed air is admitted through the inlet passageway 20 to the annular chamber 22. While in the chamber 22, the pressure acting on the ring 33 lifts it from the contact with the seat or lip 26 so that the pressure acts on the diaphragm 34. With the pressure applied to diaphragm 34, it is bent away from its contact with the annular ring 33 allowing the air under pressure to enter the space 39 and pass through the ports 40 into the chamber 37, to raise the pressure therein. When the pressure in the chamber 37 reaches a certain value, it acts in conjunction with the tendency of the ring 33 and the diaphragm 34 to resume their normal unstressed positions to overcome the pressure holding the ring and diaphragm off of the lip 26. At this time the ring'is again reseated on the lip 26 to cut off flow into the outlet passageway 21. The result of this action is that a quantity of the compressed gaseous medium passes into the outlet passageway 21 and travels therethrough and out the resonator such as 16. As the pulse passes through the passageway, a return pulse is impinged back against the diaphragm 34 causing it to be lifted from its contact with the ring 33 allowing a second pulse to enter the outlet passageway 21. Due to the particular frequency characteristics of the diaphragm 34 and the length of travel of the pulses in the outlet passage 21, the diaphragm 34 and the ring 31 vibrate to allow a series of pulses to pass through the outlet passageway 21 and throughthe horn such as 16. The vibrator means 32 thus converts a substantially constant flow of pressurized gas into a pulsating flow as explained in the US. Pat. No. 2,579,784.

The bleed means for the chamber 37 which is illustrated as a small orifice or hole 41 enables the pressure that accumulates in the chamber 37 to be bled ofi' during periods of no operation of the device so that in starting the device up, the pressure in the chamber 37 will not be of such magnitude to prevent the beginning of the vibration of the vibrator means. 32.

In a sound device similar to 10 having a single horn such as 16, the outlet passageway 21 has two portions 28 and 29 which may have a point of intersection with a curved or deflecting surface to facilitate the propagation of the pulsating flow around the substantially right angle turn.

In a sound device with a single horn or resonator, it has been found desirable to provide means for changing the boundary layer characteristics of the flow through the second portion such as 29 and the resonator 16. An example of such a means is illustrated in FIG. 5 and comprises an inspirator generally indicated at 50 which is located adjacent the point of intersection between the first portion 28 and the second portion 29. As illustrated, the inspirator 50 has a plurality of output ports 51 which are circumferentially spaced around the surface defining the second portion 29. The ports 51 are connected by passages such as 52 to an inlet port 53 which is adapted to be connected to a separate source of pressurized gaseous medium'such as compressed air which has appropriate valvemeans for controlling the admission of the second source into the inlet port 53.

During operation of the sound device, the operator can activatethe inspirator 50 by connecting the second source of compressed gas to the inspirator means 50. The gas will flow through the inlet port 53 through the passageways 52 to the outlet ports 51 and along the surface of the second portion 29 and the resonator or horn associated therewith. This flow will change the boundary layer characteristics along these surfaces and their effect on the flow of the pulsating compressed air flowing through the outlet passageway 21, and will result in changing the resistance and impedance to the flow of the pulsating gas through the horn. Such a change in the resistance or impedance causes a variation in the tone produced by the device with the variation being approximately one full tone higher.

As described hereinabove, a sound device such as 10 has two horn or resonators l6-and 17 each supplied by a pulsating flow controlled by a single vibrator means 32. If as illustrated, the resonator 16 is of a different size than the resonator 17, different 'tones willv be produced therefrom. However, due to the difference in the size of the two horns or resonators l6 and 17 each will have a different resistance or impedance to the flow of the pulsating gaseous medium. For example, the greater size of the horn 16 will have a greater impedance to the flow of the pulsating medium than the smaller size horn 17. Due to the diflerence in the im pedance, the strength of the sound generated in each of the resonators 16 and 17 will be different since the pulsating flow will travel the path of least resistance.

In order to correct this difference in impedance to the flow, the device 10 is provided witha means for balancing the flow between the two horns such as 16 and 17. One example of a balancing means is the inspirator means such as 50 (FIG. 5) which is placed in the passageway portion of the horn having the greatest impedance. By actuating the inspirator means, the impedance created at the boundary layer of the inner sur-. face of the horn and passageway is reduced and thus the gaseous medium tends to flow equally out of each of the resonators l6 and 17.

Another means for balancing the flow between the two resonators 16 and 17 is the use of a splitter 55 (FIG. 3) which extends along the portion 28 of the passageway 21 to the base 28a or the point of intersection with the second or third portions 29 and 30. The splitter 55 is a partition which terminates adjacent the diaphragm 34 and slightly below the plane of the lip 26. The partition 55 separates the pulsating flow into two substantially equal portions as it progresses along the first portion 28 of the outlet passageway 21 and prevents the pulsating flow from passing to the resonator having the least resistance.

Another example of a means for balancing the flow of the pulsating medium through the portions 29 and 30 of the outlet passageway 21 is the provision of an impedance means 56 in the portion 30 of the outlet passageway 21 which is associated with the resonator having at least the impedance to the flow of the pulsating flow. The impedance means 56 is illustrated in FIG. 5 or an annular ring 57 received in the portion 30 and having a reduced diameter orifice 58 which resists or impedes the flow of the pulsating fluid through the passageway 30. The annular ring 57 which acts as a choke on the pulsating flow has its orifice 58 selected to provide the right amount of impedance or restriction to the flow so that the impedance of both passageways 29 and 30 are matched and thus each passageway receives a substantially equal portion of the flow and the resonators or horns associated with the two passageways will produce a sound of the same strength.

Another method of applying an impedance means to balance the flow through the two passageway portions 29 and 30 is to replace the portion 30 with-a third portion 60 (FIG. 6) having a curved or tortuous path. By forcing the pulsating gaseous medium entering the third passageway 60 to follow a curved path, the flow of the pulsating gaseous media will be impeded. With the proper selection of the path to provide a desired tortuous path, the impedance of the flow of the medium therethrough can be matched to the impedance of the flow through the portion 29 and into its associated horn. Thus with the proper selection of the curved or tortuous path, the impedance of the gaseous flow through both passageways can be balanced to insure the same strength of the two sounds generated by the two different horns or resonators.

Asmentioned above, the T-shaped outlet passageway having a first portion 28 and second and third portions 29 and 30 can be utilized to drive two horns having the same impedance characteristics. In order to facilitate the movement of the pulsating flow through the substantially right angle turn formed by the junction of the second and third portions with the first portion 28, a deflecting block 65 having deflecting surfaces 66 and 67 can be positioned at the base 28a on the centerline of the passageway portion 28. The block tionship to the centerline of portion 28. For example, if it is mounted at the position 65a, shown in broken lines, it serves to impede the pulsating flow into the portion 30 while aiding in reflecting the pulsating flow into both the portions 30 and 29. If it is located in a position 65b, shown in broken lines, it would impede the flow into portion 29. By proper selection of the offset positions towards either the portion 29 or portion 30, the impedance of the flow through portions 29 and 30 and their respective resonators could be balanced to obtain the same strength of sound emitting from each born.

In each of the above examples of means used to balance the flow in each of the second and third portions to obtain substantially the same strength from the sound emitting from their respective horns, a single means was utilized. It is within the scope of the present invention to use a combination of means, such as the partition 55 and the inspirator 50. Thus during operation of the sound device 10, the strength of the sound produced in each of the horns associated with passageways 29 and 30 would be substantially the same and during periodic or intermittent operation of the inspirator 50, the tone of the sound produced by the horn or resonator associated with the passageway 29 would be varied. It is also contemplated that the partition 55 could be utilized with the choke 57 or with the tortuous path of the portion if desired.

Of course it would be obvious to those skilled in the art that the distance from the lip 26 to the base 280 along with the sonic characteristics of the resonators l6 and 17 are selected to be compatible with the frequency of the pulsating flow created by the vibrator means 32. It is also obvious that a person skilled in the art would shape the various passageways such as outlet passageway 21 to insure the best propagation of the pulsating flow through the device.

Although various minor modifications might be suggested by those versed in the art it should be understood that we wish to emply within the scope of the patent warranted hereon all such embodiments as reasonably and properly come within the scope of our contribution to the art.

We claim as our invention:

1. In a sound device having a housing with an inlet passageway for receiving a pressurized gaseous medium from a source and an outlet passageway in communication with a horn, the housing having a diaphragmtype vibrator means between the inlet and outlet passageways to convert a constant flow of gaseous medium into a pulsating flow moving through the outlet passageway, the improvement comprising the outlet passageway having a first portion extending from adjacent to the vibrator means and a second portion extending from a point of intersection with the first portion at an angle thereto so that foreign matter entering. the horn does not accumulate adjacent the vibrator means to interfere with its operation, and an inspirator means having outlet ports in communication with the outlet passageway adjacent to the point of intersection of the first and second portions, said outlet ports being in communication with an inlet port adapted to be connected to a separate source of pressurized gaseous medium so that the medium from the second source entering the outlet passageway through said outlet ports changes the boundary layer impedance characteristics of the second portion and the born to the movement of the pulsating flow therein to increase the tone of a sound created by the sound device.

2. In a sound device according to claim 1, wherein the outlet port of the inspirator means are circumferentially spaced around a surface forming the second portion of the outlet passageway.

3. In a sound device having a housing with an inlet passageway for receiving a pressurized gaseous medium from a source and an outlet passageway, the housing having a diaphragm-type vibrator means between the inlet and outlet passageways to convert a constant flow of gaseous medium into a pulsating flow moving through the outlet passageway, the improvement comprising the outlet passageway having a first portion extending from adjacent to the vibrator means and intersecting a second and third portion each of which extends at an angle to the first portion, and a pair of horns with each of said second and third portions in communication with a separate horn of said pair so that a portion of the pulsating flow in the first portion of the out-- let passageway enters each of the second and third portions to be emitted from the respective horns and foreign matter entering the horn does not accumulate adjacent the vibrator means to interfere with its operation.

4. In a sound device according to claim 3, which includes means for balancing the portions of the pulsating flow in each of the second and third portions of the outlet passageway so that the strength of the sound from each of the two horns is substantially equal.

5. In a sound device having a housing with an inlet passageway for admitting a gaseous medium under pressure into a chamber and having an. outlet passageway with an inner end extending into the chamber, vibrator means disposed in the chamber and in contact with the inner end of the outlet passageway to control the flow of medium from the chamber into the outlet passageway and to create a pulsating flow therein, the improvement comprising the outlet passageway havinga first portion extending from the inner end away from the'chamber and intersecting a second and third portion which each extends at an angle to the first portion, said second and third portions each having a resonator in communication therewith to create a sound signal from the passage of the pulsating flow of medium therethrough so that the single vibrator provides the pulsating flow for at least two resonators, whereby foreign matter entering either of the resonators is not accumulated adjacent the inner end of the first portion to interfere with the operation of the vibrator means.

6. In a sound device according to claim wherein the resonator attached to the second portion has a greater impedance to the pulsating flow of the medium than the resonator attached to the third portion, and wherein the device further includes means for balancing the pulsating flow between the two resonators so that the strength of the sounds emitted therefrom are substantially the same.

7. In a sound device according to claim 6, wherein the means for balancing comprises a partition disposed in the first portion of the outlet passageway for separating the'pulsating flow into two distinct portions prior to their entrance into the second and third portions res ectively.

. In a sound device according to claim 6, wherein the means for balancing comprises control means for varying resistance of the boundary layer of one of the resonators which control means varies the tone of the sound produced by said one horn.

9. In a sound device according to claim 8, wherein the control means comprises a plurality of outlet ports circumferentially spaced around the second portion, said outlet ports being in communication with an inlet port which is adapted to be connected to a second source of compressed gases so that the compressed gases of the second source pass through the outlet ports and flow along the surface of thesecond portion of the outlet passageway and the resonator associated therewith.

10. In a sound device according to claim 6, wherein the means for balancing comprises impedance means disposed in'the third portion of the outlet passageway to restrict the flow of the pulsating fluid therethrough.

11. In a sound device according to claim 10, wherein the impedance means comprises a means defining a restricted orifice in the third portion of the outlet passageway.

12. In a sound device according to claim 10, wherein the impedance means comprises a portion of the third portion of the outlet passageway having a curved path.

13. In a sound device according to claim 11, wherein the impedance means comprises a deflecting means disposed at the point of junction of the first portion and the second and third portions of the outlet passageway, said deflecting means being offset towards the third portion of the outlet passageway to, impede the pulsating flow into the third portion of the outlet passageway. 

1. In a sound device having a housing with an inlet passageway for receiving a pressurized gaseous medium from a source and an outlet passageway in communication with a horn, the housing having a diaphragm-type vibrator means between the inlet and outlet passageways to convert a constant flow of gaseous medium into a pulsating flow moving through the outlet passageway, the improvement comprising the outlet passageway having a first portion extending from adjacent to the vibrator means and a second portion extending from a point of intersection with the first portion at an angle thereto so that foreign matter entering the horn does not accumulate adjacent the vibrator means to interfere with its operation, and an inspirator means having outlet ports in communication with the outlet passageway adjacent to the point of intersection of the first and second portions, said outlet ports being in communication with an inlet port adapted to be connected to a separate source of pressurized gaseous medium so that the medium from the second source entering the outlet passageway through said outlet ports changes the boundary layer impedance characteristics of the second portion and the horn to the movement of the pulsating flow therein to increase the tone of a sound created by the sound device.
 2. In a sound device according to claim 1, wherein the outlet port of the inspirator means are circumferentially spaced around a surface forming the second portion of the outlet passageway.
 3. In a sound device having a housing with an inlet passageway for receiving a pressurized gaseous medium from a source and an outlet passageway, the housing having a diaphragm-type vibrator means between the inlet and outlet passageways to convert a constant flow of gaseous medium into a pulsating flow moving through the outlet passageway, the improvement comprising the outlet passageway having a first portion extending from adjacent to the vibrator means and intersecting a second and third portion each of which extends at an angle to the first portion, and a pair of horns with each of said second and third portions in communication with a separate horn of said pair so that a portion of the pulsating flow in the first portion of the outlet passageway enters each of the second and third portions to be emitted from the respective horns and foreign matter entering the horn does not accumulate adjacent the vibrator means to interfere with its operation.
 4. In a sound device according to claim 3, which includes means for balancing the portions of the pulsating flow in each of the second and third portions of the outlet passageway so that the strength of the sound from each of the two horns is substantially equal.
 5. In a sound device having a housing with an inlet passageway for admitting a gaseous medium under pressure into a chamber and having an outlet passageway with an inner end extending into the chamber, vibrator means disposed in the chamber and in contact with tHe inner end of the outlet passageway to control the flow of medium from the chamber into the outlet passageway and to create a pulsating flow therein, the improvement comprising the outlet passageway having a first portion extending from the inner end away from the chamber and intersecting a second and third portion which each extends at an angle to the first portion, said second and third portions each having a resonator in communication therewith to create a sound signal from the passage of the pulsating flow of medium therethrough so that the single vibrator provides the pulsating flow for at least two resonators, whereby foreign matter entering either of the resonators is not accumulated adjacent the inner end of the first portion to interfere with the operation of the vibrator means.
 6. In a sound device according to claim 5 wherein the resonator attached to the second portion has a greater impedance to the pulsating flow of the medium than the resonator attached to the third portion, and wherein the device further includes means for balancing the pulsating flow between the two resonators so that the strength of the sounds emitted therefrom are substantially the same.
 7. In a sound device according to claim 6, wherein the means for balancing comprises a partition disposed in the first portion of the outlet passageway for separating the pulsating flow into two distinct portions prior to their entrance into the second and third portions respectively.
 8. In a sound device according to claim 6, wherein the means for balancing comprises control means for varying resistance of the boundary layer of one of the resonators which control means varies the tone of the sound produced by said one horn.
 9. In a sound device according to claim 8, wherein the control means comprises a plurality of outlet ports circumferentially spaced around the second portion, said outlet ports being in communication with an inlet port which is adapted to be connected to a second source of compressed gases so that the compressed gases of the second source pass through the outlet ports and flow along the surface of the second portion of the outlet passageway and the resonator associated therewith.
 10. In a sound device according to claim 6, wherein the means for balancing comprises impedance means disposed in the third portion of the outlet passageway to restrict the flow of the pulsating fluid therethrough.
 11. In a sound device according to claim 10, wherein the impedance means comprises a means defining a restricted orifice in the third portion of the outlet passageway.
 12. In a sound device according to claim 10, wherein the impedance means comprises a portion of the third portion of the outlet passageway having a curved path.
 13. In a sound device according to claim 11, wherein the impedance means comprises a deflecting means disposed at the point of junction of the first portion and the second and third portions of the outlet passageway, said deflecting means being offset towards the third portion of the outlet passageway to impede the pulsating flow into the third portion of the outlet passageway.
 14. In a sound device according to claim 6, which further includes control means for varying the resistance of the boundary layer of said one portion disposed in one of said second or third portions so that the tone of the sound produced by the resonator associated with said portion is varied. 